The practice of transplantation has developed to the point that the technical aspects of surgery are not limiting. The major remaining obstacles, other than the shortage of organs, are associated with rejection and with immunosuppressive therapy employed to prevent or control it. Recently, major advances in technical procedures and in the understanding of molecular and cellular processes in immunology have been made. These advances will continue to lead to the development of more efficacious and less toxic immunosuppressive regimens and agents. However, at the present time there is no mechanism to establish and coordinate the multi-center clinical trials required to evaluate the effectiveness of current and new immunosuppressive protocols. A cooperative clinical trial approach, involving 8 kidney transplant units throughout the U.S. would expedite the process of evaluating new immunosuppressive protocols and speed the transfer of basic knowledge to clinical application. The transplant units will be awarded under a separate Cooperative agreement (UO-1) and this RFP is for the Data Coordinating Center only. The TSUs will be awarded in August, 1991. A copy of RFA-NIH-NIAID-AI-90-07 for the Cooperative Clinical Trial in Transplantation will be included with the RFP when mailed to respondents. The Data Coordinating Center shall be involved in all aspects of the trial from the inception of planning and organizational phase through the final data analysis and reporting of the results. As an integral part of the multicenter project, the coordinating center will be responsible for participating in Steering Committee necessary to contribute substantially to the final design of the study, designing the system for data collection, entry, and management of data, developing and implementing a randomization procedure for assigning patient treatments in the clinical trial portion of study and proposing methods for blinding the medication/biologicals used in the study, receiving, distributing, and labelling treatment devices, medications and placebos for the clinical trial and providing statistical analysis and reporting and contract monitoring based on interim data.